Electric switch-box



(No Model.) 2 Sheets-Sheet 1.

J. H. DEAN. ELECTRIC SWITCH BOX.

No. 449,362. I Patented Mar. 31,1891.

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(No Model.) I, 2 Sheets-Sheet 2.

J. H. DEAN.

ELECTRIC SWITCH BOX.

No. 449,362. Patented Mar. 81, 1891.

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vu/enior UNITED STATES PATENT OFFICE.

JAMES H. DEAN, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO BARRON D. SOUTI-IARD, OF SAME PLACE, AND IL-LIAM PERKINS, OF ARMADA, MICHIGAN.

ELECTRIC SWITCH-BOX.

SPECIFICATION forming part of Letters Patent No. 449,362, dated March 81, 1891.

Application filed November 4, 1890. Serial No. 370,328. (No model.)

To all whom it may concern:

Be it known that I, JAMES II. DEAN, of Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain Improvements in Electric SwitclrBoxes, of which the following is a specification.

My invention relates to electric switches of the class adapted for use in connect-ion with electric motors; and its object is to provide a resistance switch-box, by means of which more or less current may be switched through the motor and which at the same time will perform the duty of an automatic cut-out adapted to completely break the circuit of the m0- tor upon the instant the current in or from the mains is cut oif or very materially weakened, to the end that when the current is again turned on in the mains the armature and other windings of the motor will be removed from the danger of being burned out by a strong current suddenly passing through the same.

The invention consists in what I may call a resistance-drum, provided in connection with a suitable commutator upon a central and preferably vertical shaft movably connected with a suitable switch-lever adapted to make contact with a suitable contact-ring, a contact-brush bearing on said commutator, and an armature provided on said resistancedrum in position to be magnetically engaged by a suitable clectro-magnet included in the circuit of the motor when said circuit has been completed by the turning of the switchlever and the cutting out of all the resistance, and means whereby said shaft, lever, and drum are instantly turned back and the switch-lever carried onto the insulated segment of the ring when current ceases to pass through the electromagnet.

The invention consists, further, in various details of construction and in combinations hereinafter described, and particularly pointed out in the claims.

My invention will be more readily understood by reference to the accompanying drawings, in which- Figure 1 is a transverse sectional elevation of an electric switch-box embodying my invention. Fig. 2 is a plan view of the same as seen from the line 5C of Fig. 1. Fig. 3 is a top view of the switch-box. Figeis a diagrammatic view illustrating the connections between the various parts of the switch-box, the mains, and the electric motor.

As shown in Figs. 1 and 2, the shaft 2 is provided with the large head 3 and with the arms or spiders a and 5, upon which arms are secured the disks 0 and 7, respectively. These disks are made of insulating material, such as hard rubber or insulating fiber, and form the heads of what I have called the resistancedrum. Between these disks extend the resistance-coils 8, groups of which are connected with the corresponding segments of the commutator 9. The contact brush 10, provided on the insulated post 11, presses firmly against the surface of the commutator 9 at all times.

The resistance-coils 8 may be of any number, foursets of three each being shown. Beginning with the set 12, connected with the first segment of the commutator 9, the sets 13, ll, and 1-5 and the individual coils thereof are connected in series, legs 16, 17, and 18 passing from between the segments of the commutator, as shown. Any manner of resistance may be used in making up the drum; but I preferably employ a small wire provided in the form of coiled wire springs, all convolutions of the same beingentirely separate from each other. In this way a great length of resistance-wire is included within a small space. The lower end of the shaft is held in the journal 19, provided on the bottom 20 of 8 the inclosing box 21. The clock-spring 22 is provided in connection with said lower end, having one end fastened thereto and the other end fastened to the journal-block 19 in such a way as to constantly tend to turn the shaft 2 back. A cap 23 is preferably secured over the spring 22 to keep the same in place. On the top 24: of the box is provided the contactring 25, (shown most clearly in Fig. 3,) and having the segment 26 of insulating material, upon which the contact 27 of the lever 28 normally rests. The connection between the contact-lever 2S and the shaft 2 consists in the bolt 29, permanently screwed into the head 3 of the shaft, the distance between the head 100 of the bolt 29 and theshoulder of the bolt pressing against the upper surface of the head 3 being greater than the thickness of the end of the lever, so that the lever is left to freely rotate about the shank of the bolt 29. A pin 30 is provided in the head 3, adapted to engage with a pin 31, provided in the circular slot 32, forming a recess in the end of the lever 28. It will be seen that the pin31 stands behind the pin 30. \Vhen the lever 28 is turned around in the direction of the arrow shown in Fig. 3, thegpins will engage, and the shaft 2, the resistance-d rum, and the commu- I tator will be rotated.

The electro-magnet 33 is provided in the bottom of the box in the position indicated in Figs. 1 and 2,-the same being energized by current passing through the same from a direct connection with the electric mains. The core 34 of'theelectro-magnet 33 is adapted to magnetically engage the armature 35, provided on the under side of the disk 7 and so placed as to come directly over the core when the shaft has been rotated, so asto bring the last segment 36 under the contact-brush 10, or, in other words, when the whole resistance has been out out. At this time it will be seen that the electro-magnet 33 will be energized very strongly, so as to hold the drum and shaft against the force of the counteracting clockspring 22. In order to turn the drum around such a distance as to bring the armature above the core 34, the contact-lever is turned clear around on the contact-ring until theend of the lever comes against the side 37 of the stop 38, formed by a shoulder in the insulatingsegment 26 orin any otherconvenient manner. WVith the lever in this position all of the resistance will be cut out and the full amount of current will pass through the motor in the circuit of which the switch-box is included. Suppose at this time current should be shut off in the mains. The motor would immediately slow down, and at the same time the magnet 33, being de-energized, the armature 35 and the drum will be released, whereupon the shaft, with the contact-lever, will be immediately turned back by the force of the clockspring, so as to carry the contact-lever'olf of the metal portion of the ring 25 and upon the insulated segment thereof. If the current be now turned on in the mains, it will be seen that no damage can result to the armature of the motor, as no current can pass through the same until the switch-lever has been turned about by thehand of the operator. The usual copper rivet or plate is preferably provided on the end of the core 34 or upon the armature 35 to prevent the sticking of the armature to the core after current has ceased to pass through the same. The magnet-cores are preferably wound in such a way as to be so farde-energized as to release the armature when the current in the mains falls below a safe limit.

It is obvious that the switch-lever, being attached, as it is, movably to the top of the shaft, may be moved back at any time onto the insulated segment of the ring, regar dless of whether the armature and electro-magnet' are in engagement or not. After so breaking the circuit of the motor the magnet would be demagnetized, and the armature being released the shaft and drum would immediately turn back, so as to bring the first segment of the commutator under the contact-brush, thereby leaving the switch-box in perfect readiness for again switching on the current to start the motor.

In Fig. 4 is shown the circuit preferably used for connecting my device with the motor. The mains 40 and 41 are supplied with current from any suit-able source. From the main 40, representing one electric pole, the circuit may be traced by the branch 42 to the binding-post 43, from whence the circuit extends through the electro-magnet 33 to the binding-post 44, and from thence through the field-windings 45 to the binding-post 46. From the binding post 46 the circuit extends through the shaft 2, and from the switch -lever 28, in connection therewith, to the contact-ring 25, and from thence by the connection 47 to the bindingpost 48 and the main 41. In this way the direct circuit through the field-windings of the motor is completed. From the point 49 the shunt-circuit may be traced through the armature by way of the commutator and brushes to the binding-post 50, and from thence to the last segment 36 ofthe commutator 9,from whence it passes through all the resistance-coils 15,

14, 13, and 12 to the first segmentof the commutator, against which the brush 10 bears. From the brush. the circuit extends through the connection 51 to the binding-post 46, where the shunt-circuit joins with the main circuit. Thus it will be seen that the resistance isineluded directly in the armature-shunt.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1 1. The combination, in an electric switchbox, of a central shaft provided with a contact-brush, a contact-ring, a resistance-drum provided on said shaft, anarmature provided on said drum, and an electro-magnet adapted to magnetically engage said armature, and means whereby said shaft when not held by the electro-magnet or by the switch-lever is turned back and held in its normal position, substantially as and for the purpose described.

2. In a switch-box, the combination, with the shaft, of a contact-lever with which said shaft is adapted to turn, a contact-ring arranged in connection with said lever, an armature arranged in connection with said shaft, and an electro-magnet provided in the circuit in which said ring and switch-lever are included and adapted to magnetically engage said armature, whereby saidshaft with the switch-lever is held while current is pass ing through said electro-magnet and released.

when current ceases to How through the same, substantially as described.

3. The combination, in a device of the class described, of the central shaft with the switchlcver, the contact-ring having the insulatingsegment, the resistance-drum provided with several sets of resistance devices, a commutator provided on said shaft, but insulated therefrom and connected with said resistance devices, and a contact-brush adapted to press on said commutator, substantially as described.

4-. The combinatiomin a device of the class described, of the contact-ring having the insulating-segment with the switch-lever adapted to make contact with said contact-ring, a central shaft upon which said switch lever is pivoted, a spring adapted to restore said shaft with the switch-lever to their normal positions after being rotated forward, a resist= ance-drnm arranged on said shaft in connection with a suitable commutator, a brush adapted to bear on the surface of said commutator, an armature provided on the end of said resistance-drum, and an clectro-magnet adapted to magnetically engage said armature, substantially as described.

5. The combination,in a device of the class described, of the central vertical shaft with switch-lever arranged thereon, the contactring having the insulated segment upon which said switch-lever normally bears, the arms provided on said shaft, the disks of insulatin g material arranged thereon,resistance-coils extending between said disks, the commutatorprovided on said shaft but insulated therefrom, the segments of said commutator being connected with corresponding sets of resistance-coils, a contact-brush adapted to bear on the surface of said commutator, the lower end of the said shaft provided in a suitable journal, a cloclespring arranged in connection with said end of the shaft, an armature arranged on one of said disks, and an electromagnet adapted to engage said armature, sub stantialiy as described.

6. The combination, in an electric switchboX, of the central shaft 2, with the arms 4 and 5 provided thereon, the disks 6 and 7, resistance-coils extending between said disks, the commutator 9, made up of insulated scg ments, said segments being connected with corresponding sets of resistance-coils, and a contact-brush adapted to bear on said commutator, substantially as described.

'7. The combination, in an electric switchbox, of the shaft 2, with the journal 19, the clock-spring 22, arranged in connection with said shaft and tending to rotate the same backwardly, the switch-lever 28, pivoted on said shaft and by means of which said shaft may be revolved in a forward direction, the contact-1 in g 25 ,with which said lever 2 Sis adapted to make contact, the insulating or insulated segment 20 of said ring, the arms 4 and 5, the disks 6 and 7, the commutator 9, the resistance-coils arranged in connection with the segments in said commutator, the brush 10, adapted to bear on the surface of said com mutator, said commutator-segments being insulated from each other and from the shaft, and means whereby said disks, shaft, and switchdever are magnetically held in position, substantially as and for the purpose specified.

8b The combination, in an electric switchbox, of the contact-ring having the insulated segment and arranged in connection with a source of electricity, the switch-lever 28, having the contact-brush 27, adapted to bear on said contact-ring, the shaft 2, upon which said switch-lever is pivoted, said shaft being connected with the field-coils of the motor, the eleetro-magnet 33,included bet ween said fieldcoils and the opposite pole of said source of electricity, the arms i and 5, the disks 6 and 7 of insulating material, the resistance-coils 8, connected in sets with corresponding segments of said commutator, the contact-brush 10, connected with one side of the armature, the other side of the armature being connected with the last segment of said commutator, the clock-spring 22, arranged in connection with the lower end of said shaft 2, the armature 35, and a stop arranged to engage said switchlever when in either of its extreme positions, substantially as described.

In testimony whereof I have hereunto set my hand this 29th day of October, 1890.

JAMES H. DEAN. In presence of A. M. GASKILL, C. G. HAwLnY. 

